time/time.h

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 96 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 /*
  20  *      ANSI Standard: 4.12 DATE and TIME       <time.h>
  21  */
  22
  23 #ifndef _TIME_H
  24
  25 #if     !defined(__need_time_t) && !defined(__need_clock_t)
  26 #define _TIME_H         1
  27 #include <features.h>
  28
  29 __BEGIN_DECLS
  30
  31 #endif
  32
  33 #ifdef  _TIME_H
  34 /* Get size_t and NULL from <stddef.h>.  */
  35 #define __need_size_t
  36 #define __need_NULL
  37 #include <stddef.h>
  38 #endif /* <time.h> included.  */
  39
  40
  41
  42 #ifdef  _TIME_H
  43
  44 /* This defines CLOCKS_PER_SEC, which is the number of processor clock
  45    ticks per second.  */
  46 #include <timebits.h>
  47
  48 /* This is the obsolete POSIX.1-1988 name for the same constant.  */
  49 #ifdef  __USE_POSIX
  50 #define CLK_TCK         CLOCKS_PER_SEC
  51 #endif
  52
  53 #endif /* <time.h> included.  */
  54
  55
  56 #if     !defined(__clock_t_defined) &&                  \
  57         (defined(_TIME_H) || defined(__need_clock_t))
  58 #define __clock_t_defined       1
  59
  60 /* Returned by `clock'.  */
  61 typedef long int clock_t;
  62
  63 #endif /* clock_t not defined and <time.h> or need clock_t.  */
  64 #undef  __need_clock_t
  65
  66 #if     !defined(__time_t_defined) &&                   \
  67         (defined(_TIME_H) || defined(__need_time_t))
  68 #define __time_t_defined        1
  69
  70 #include <gnu/types.h>
  71
  72 /* Returned by `time'.  */
  73 typedef __time_t time_t;
  74
  75 #endif /* time_t not defined and <time.h> or need time_t.  */
  76 #undef  __need_time_t
  77
  78
  79 #ifdef  _TIME_H
  80 /* Used by other time functions.  */
  81 struct tm
  82 {
  83   int tm_sec;                   /* Seconds.     [0-61] (2 leap seconds) */
  84   int tm_min;                   /* Minutes.     [0-59] */
  85   int tm_hour;                  /* Hours.       [0-23] */
  86   int tm_mday;                  /* Day.         [1-31] */
  87   int tm_mon;                   /* Month.       [0-11] */
  88   int tm_year;                  /* Year - 1900.  */
  89   int tm_wday;                  /* Day of week. [0-6] */
  90   int tm_yday;                  /* Days in year.[0-365] */
  91   int tm_isdst;                 /* DST.         [-1/0/1]*/
  92   long int tm_gmtoff;           /* Seconds west of UTC.  */
  93   __const char *tm_zone;        /* Timezone abbreviation.  */
  94 };
  95
  96 #endif /* <time.h> included.  */
  97
  98
  99 #ifdef  _TIME_H
 100 /* Time used by the program so far (user time + system time).
 101    The result / CLOCKS_PER_SECOND is program time in seconds.  */
 102 extern clock_t clock __P ((void));
 103
 104 /* Return the current time and put it in *TIMER if TIMER is not NULL.  */
 105 extern time_t time __P ((time_t *__timer));
 106
 107 /* Return the difference between TIME1 and TIME0.  */
 108 extern double difftime __P ((time_t __time1, time_t __time0))
 109      __attribute__ ((__const__));
 110
 111 /* Return the `time_t' representation of TP and normalize TP.  */
 112 extern time_t mktime __P ((struct tm *__tp));
 113
 114 /* Subroutine of `mktime'.  Return the `time_t' representation of TP and
 115    normalize TP, given that a `struct tm *' maps to a `time_t' as performed
 116    by FUNC.  Keep track of next guess for time_t offset in *OFFSET.  */
 117 extern time_t __mktime_internal __P ((struct tm *__tp,
 118                                       struct tm *(*__func) (const time_t *,
 119                                                             struct tm *),
 120                                       time_t *__offset));
 121
 122
 123 /* Format TP into S according to FORMAT.
 124    Write no more than MAXSIZE characters and return the number
 125    of characters written, or 0 if it would exceed MAXSIZE.  */
 126 extern size_t strftime __P ((char *__s, size_t __maxsize,
 127                              __const char *__format, __const struct tm *__tp));
 128
 129 #ifdef __USE_MISC
 130 /* Parse S according to FORMAT and store binary time information in TP.
 131    The return value is a pointer to the first unparsed character in S.  */
 132 extern char *strptime __P ((__const char *__s, __const char *__fmt,
 133                             struct tm *__tp));
 134 #endif
 135
 136
 137 /* Return the `struct tm' representation of *TIMER
 138    in Universal Coordinated Time (aka Greenwich Mean Time).  */
 139 extern struct tm *gmtime __P ((__const time_t *__timer));
 140
 141 /* Return the `struct tm' representation
 142    of *TIMER in the local timezone.  */
 143 extern struct tm *localtime __P ((__const time_t *__timer));
 144
 145 #ifdef  __USE_REENTRANT
 146 /* Return the `struct tm' representation of *TIMER in UTC,
 147    using *TP to store the result.  */
 148 extern struct tm *__gmtime_r __P ((__const time_t *__timer,
 149                                    struct tm *__tp));
 150 extern struct tm *gmtime_r __P ((__const time_t *__timer,
 151                                  struct tm *__tp));
 152
 153 /* Return the `struct tm' representation of *TIMER in local time,
 154    using *TP to store the result.  */
 155 extern struct tm *__localtime_r __P ((__const time_t *__timer,
 156                                       struct tm *__tp));
 157 extern struct tm *localtime_r __P ((__const time_t *__timer,
 158                                     struct tm *__tp));
 159 #endif
 160
 161 /* Compute the `struct tm' representation of *T,
 162    offset OFFSET seconds east of UTC,
 163    and store year, yday, mon, mday, wday, hour, min, sec into *TP.  */
 164 extern void __offtime __P ((__const time_t *__timer,
 165                             long int __offset,
 166                             struct tm *__TP));
 167
 168 /* Return a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 169    that is the representation of TP in this format.  */
 170 extern char *asctime __P ((__const struct tm *__tp));
 171
 172 /* Equivalent to `asctime(localtime(timer))'.  */
 173 extern char *ctime __P ((__const time_t *__timer));
 174
 175
 176 /* Defined in localtime.c.  */
 177 extern char *__tzname[2];       /* Current timezone names.  */
 178 extern int __daylight;          /* If it is daylight savings time.  */
 179 extern long int __timezone;     /* Seconds west of UTC.  */
 180
 181 /* Set time conversion information from the TZ environment variable.
 182    If TZ is not defined, a locale-dependent default is used.  */
 183 extern void __tzset __P ((void));
 184
 185 #ifdef  __USE_POSIX
 186 /* Same as above.  */
 187 extern char *tzname[2];
 188
 189 /* Return the maximum length of a timezone name.
 190    This is what `sysconf (_SC_TZNAME_MAX)' does.  */
 191 extern long int __tzname_max __P ((void));
 192
 193 extern void tzset __P ((void));
 194 #ifdef  __OPTIMIZE__
 195 #define tzset() __tzset()
 196 #endif /* Optimizing.  */
 197 #endif
 198
 199 #ifdef  __USE_SVID
 200 extern int daylight;
 201 extern long int timezone;
 202
 203 /* Set the system time to *WHEN.
 204    This call is restricted to the superuser.  */
 205 extern int stime __P ((__const time_t *__when));
 206 #endif
 207
 208
 209 /* Nonzero if YEAR is a leap year (every 4 years,
 210    except every 100th isn't, and every 400th is).  */
 211 #define __isleap(year)  \
 212   ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
 213
 214
 215 #ifdef __USE_MISC
 216 /* Miscellaneous functions many Unices inherited from the public domain
 217    localtime package.  These are included only for compatibility.  */
 218
 219 /* Like `mktime', but for TP represents Universal Time, not local time.  */
 220 extern time_t timegm __P ((struct tm *__tp));
 221
 222 /* Another name for `mktime'.  */
 223 extern time_t timelocal __P ((struct tm *__tp));
 224
 225 /* Return the number of days in YEAR.  */
 226 extern int dysize __P ((int __year));
 227 #endif
 228
 229
 230 /* POSIX.4 structure for a time value.  This is like a `struct timeval' but
 231    has nanoseconds instead of microseconds.  */
 232 struct timespec
 233   {
 234     long int ts_sec;            /* Seconds.  */
 235     long int ts_nsec;           /* Nanoseconds.  */
 236   };
 237
 238 #ifdef __USE_POSIX
 239 /* Pause execution for a number of nanoseconds.  */
 240 extern int nanosleep __P ((__const struct timespec *__requested_time,
 241                            struct timespec *__remaining));
 242 #endif
 243
 244
 245 __END_DECLS
 246
 247 #endif /* <time.h> included.  */
 248
 249 #endif /* <time.h> not already included.  */